Ch. 6, 7, 8, & 9

Question 1

Electron microscope

Answer 1

Focuses a beam of electrons through the specimen or into its surface.

Question 2

Scanning electron microscope

Answer 2

Is especially used for detailed study of the topography of a specimen. The electron beam scans the surface of the sample usually coated with a film of gold. The excites electrons on the surface, and these secondary electrons are detected by a device that translates the pattern of electrons into an electron signal sent to a video screen. The result is a 3-D image.

Question 3

Cell fractionation

Answer 3

The process of telling cells apart and separating major organelles and other au cellular structures from one another. The equipment used is the centrifuge.

Question 4

All cells share the same basic features:

Answer 4

They are all bounded by a plasma membrane. Inside all cells is cytosol (cytoplasm). All cells contain chromosomes. And they all contain ribosomes.

Question 5

Location of DNA in eukaryotic cell:

Answer 5

Most of the DNA is in the nucleus, which is bounded by a double membrane.

Question 6

Location of DNA in prokaryotic cell:

Answer 6

DNA is concentrated in the nucleoid, which is not membrane enclosed.

Question 7

Plasma membrane

Answer 7

Functions as a selective barrier that allows passage of enough oxygen, nutrients, and wastes to service the entire cell.

Question 8

Light microscope

Answer 8

Visible light is passes through the specimen and then through glass lenses.

Question 9

Which organelle or structure is absent in plant cells?

Answer 9

centrosomes

Question 10

In plant cells, the middle lamella _____.

Answer 10

allows adjacent cells to adhere to one another

Question 11

Why are lipids and proteins free to move laterally in membranes?

Answer 11

There are only weak hydrophobic interactions in the interior of the membrane.

Question 12

The Golgi apparatus has a polarity, or sidedness, to its structure and function. Which of the following statements correctly describes this polarity?

Answer 12

Transport vesicles fuse with one side of the Golgi and leave from the opposite side.
Lipids in the membrane of the Golgi may be sorted and modified as they move from one side of the Golgi to the other.
Proteins in the membrane of the Golgi may be sorted and modified as they move from one side of the Golgi to the other.
D) polarity characteristics of the Golgi function.

Question 13

Why is glycolysis considered to be one of the first metabolic pathways to have evolved?

Answer 13

It does not involve organelles or specialized structures, does not require oxygen, and is present in most organisms

Question 14

Prokaryotes are classified as belonging to two different domains. What are the domains?

Answer 14

Bacteria and Archaea

Question 15

Zinc, an essential trace element for most organisms, is present in the active site of the enzyme carboxypeptidase. The zinc most likely functions as _____.

Answer 15

a cofactor necessary for enzyme activity

Question 16

Starting with one molecule of glucose, the energy-containing products of glycolysis are ____

Answer 16

2 NADH, 2 pyruvate, and 2 ATP

Question 17

Living organisms increase in complexity as they grow, resulting in a decrease in the entropy of an organism. How does this relate to the second law of thermodynamics?

Answer 17

As a consequence of growing, organisms cause a greater increase in entropy in their environment than the decrease in entropy associated with their growth.

Question 18

Which of the following membrane activities requires energy from ATP?

Answer 18

movement of Na+ ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid

Question 19

A noncompetitive inhibitor decreases the rate of an enzyme reaction by ___

Answer 19

changing the shape of the enzyme’s active site

Question 20

In what way do the membranes of a eukaryotic cell vary?

Answer 20

Certain proteins are unique to each membrane.

Question 21

The smallest cell structure that would most likely be visible with a standard (not super-resolution) research-grade light microscope is a _____.

Answer 21

mitochondrion

Question 22

Most cells cannot harness heat to perform work because _____

Answer 22

temperature is usually uniform throughout a cell

Question 23

Which of the following statements about the cytoskeleton is true?

Answer 23

Movement of cilia and flagella is the result of motor proteins causing microtubules to move relative to each other.

Question 24

In glycolysis, for each molecule of glucose oxidized to pyruvate

Answer 24

two molecules of ATP are used and four molecules of ATP are produced

Question 25

Why is ATP an important molecule in metabolism?

Answer 25

It provides energy coupling between exergonic and endergonic reactions

Question 26

The liver is involved in detoxification of many poisons and drugs. Which of the following structures is primarily involved in this process and, therefore, abundant in liver cells?

Answer 26

smooth ER

Question 27

Which of the following is an example of potential rather than kinetic energy?

Answer 27

a molecule of glucose

Question 28

When a molecule of NAD+ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not a proton), the molecule becomes _____.

Answer 28

reduced

Question 29

Amoebae move by crawling over a surface (cell crawling), which involves ___

Answer 29

growth of actin filaments to form bulges in the plasma membrane

Question 30

Diffusion _____

Answer 30

is a passive process in which molecules move from a region of higher concentration to a region of lower concentration

Question 31

Substrate-level phosphorylation occurs ____

Answer 31

in both glycolysis and the citric acid cycle

Question 32

When electrons move closer to a more electronegative atom, what happens? The more electronegative atom is ____

Answer 32

reduced, and energy is released

Question 33

he active site of an enzyme is the region that _____

Answer 33

is involved in the catalytic reaction of the enzyme

Question 34

The lock-and-key analogy for enzymes applies to the specificity of enzymes _____

Answer 34

binding to their substrate

Question 35

One function of both alcohol fermentation and lactic acid fermentation is to ____

Answer 35

oxidize NADH to NAD+

Question 36

A system at chemical equilibrium ___

Answer 36

can do no work

Question 37

The voltage across a membrane is called the __

Answer 37

membrane potential

Question 38

The mathematical expression for the change in free energy of a system is ΔG =ΔH - TΔS. Which of the following is (are) correct?

Answer 38

ΔG is the change in free energy.

Question 39

Cilia and flagella bend because of ____

Answer 39

a motor protein called dynein

Question 40

You are working on a team that is designing a new drug. For this drug to work, it must enter the cytoplasm of specific target cells. Which of the following would be a factor that determines whether the molecule selectively enters the target cells?

Answer 40

similarity of the drug molecule to other molecules transported by the target cells

Question 41

The sodium-potassium pump is called an electrogenic pump because it __

Answer 41

contributes to the membrane potential

Question 42

Which of the following is a major difference between prokaryotic cells and eukaryotic cells?

Answer 42

Eukaryotic cells have more intracellular organelles than prokaryotes.

Question 43

What kinds of molecules pass through a cell membrane most easily?

Answer 43

small and hydrophobic

Question 44

In respiration, beta oxidation involves the ___

Answer 44

breakdown of fatty acids

Question 45

The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction ___

Answer 45

loses electrons and loses potential energy

Question 46

According to the fluid mosaic model of cell membranes, phospholipids ___

Answer 46

can move laterally along the plane of the membrane

Question 47

In solution, why do hydrolysis reactions occur more readily than condensation reactions?

Answer 47

Hydrolysis increases entropy and is exergonic

Question 48

Which of the following is a statement of the first law of thermodynamics?

Answer 48

Energy cannot be created or destroyed.

Question 49

flagellum

Answer 49

motility structure present in some animal cells; composed of a cluster of microtubules within an extension of the plasma membrane.

Question 50

centrosome (not present in plant cells)

Answer 50

region where the cell's microtubules are initiated; contains a pair of centrioles.

Question 51

microvilli

Answer 51

projections that increases the cell's surface area

Question 52

ER

Answer 52

network of membranous sacs and tubes;active in membrane synthesis and other synthetic and metabolic processes; has rough and smooth regions

Question 53

peroxisome

Answer 53

organelle with various specialized metabolic functions; produces hydrogen peroxide as a by product, then converts it to water

Question 54

mitochondrion

Answer 54

organelle where cellular respiration occurs and mots ATP is produced

Question 55

lysosome

Answer 55

digestive organelle where macromolecules are hydrolyzed

Question 56

golgi apparatus

Answer 56

organelle active in synthesis; modification, sorting, and secretion of cell products. Has two sides (cis and trans faces). Cis face is closest to ER; is the receiving side. Trans face is on the opposite side; is the shipping side.

Question 57

ribosomes

Answer 57

complexes that make proteins; free in cytosol or bound to rough ER or nuclear envelope.

Question 58

cell wall (plant cells only)

Answer 58

outer layer that maintains cell's shape and protects cell from mechanical damage.

Question 59

nucleolus

Answer 59

middle of the nucleus. may have one or more

Question 60

plasmodesmata (plant cells only)

Answer 60

cytoplasmic channels through cell walls that connect the cytoplasms of adjacent cells

Question 61

chloroplast (plant cells only)

Answer 61

photosynthetic organelle; converts energy of sunlight to chemical energy stored in sugar molecules

Question 62

central vacuole (plant cells only)

Answer 62

prominent organelle in older plant cells; functions include storage, breakdown of waste products, and hydrolysis of macromolecules; enlargement of the vacuole is a major mechanism of plant growth.

Question 63

chromatin

Answer 63

the complex of DNA and proteins making up chromosomes.

Question 64

endomembrane system

Answer 64

includes the nuclear envelope, the ER, the Golgi apparatus, lysosomes, various kinds of vesicles and vacuoles, and the plasma membrane. This system carries out a variety go tasks in a cell, including synthesis of proteins, transport of proteins into membranes & organelles or out of the cell,metabolism and movement of lipids, and detoxification of poisons.

Question 65

smooth ER

Answer 65

Functions in synthesis of lipids, metabolism of carbohydrates, detoxification of poisons, and storage of calcium ions. produces steroids( EX: hormones).

Question 66

glycoprotein

Answer 66

proteins with carbohydrates covalently bonded to them.

Question 67

transport vesicles

Answer 67

vesicles in transit from one part of the cell to another

Question 68

phagocytosis

Answer 68

the way amoebas and many other unicellular eukaryotes eat; by engulfing smaller organisms or food particles.

Question 69

autophagy

Answer 69

when a damaged organelle or small amount of cytosol becomes surrounded by a double membrane (of unknown origin) and a lysosome fuses wight the outer membrane of this vesicle. the lysosomal enzymes dismantle the enclosed material, and the resulting small organic compounds are released tot he cytosol for reuse.

Question 70

contractile vacoules

Answer 70

pump excess water out of cell

Question 71

extracellular matrix (ECM)

Answer 71

collagen, glycoproteins, and integrins